Create different shapes of the same objects with its content
I would use a particle system. Here's one approach

Create a circle
Extrude it and scale the extrusion inward to the same radius as the base of the thing that is going up
add a lot of edge loops.
Then I would select all of the faces and delete &quot;faces only&quot;

This will create a circle with a lot of vertices.  
Next I would create a collection of objects representing the cells.  (For my example I only created a cube)
Next I would create a particle system for the circle.

Set it to hair.
Emit from vertices.
Disable random order
Set the number to match the vertices
Render as collect (object in my example)
Use the collection of cells (cube) as the collection (object)


Finally you can use a vertex group to limit which vertices so you can draw the veins where the vertices won't have cells.
My result is too rigid but you can randomize the vertices a bit and so on.
You get about half the work done automatically this way but you have to do the rest to make it organic in any way.